iMac - iMac g3 boots to black screen, runs fine

I have a Graphite iMac g3 slot drive, running 10.3. After a couple days sleep, it woke to a black screen. I've replaced the battery, reset pram, both with the button inside and with command, option, p & r keys. It chimes on startup and keys make all the appropriate noises normally heard when pressed, it goes back to sleep as programmed to. (light pulses) I pushed F15 several times because I think that's the "bright key?" When I blindly move the mouse to the bottom to open an application, I can hear the hard drive run, so it must be running whatever it is I opened. Something to note, it's possible we had a slight power outage/surge? My clocks were OK but I had my eMac screen appear very dark, but not quite black, when I woke that after being out of the house all day. I did some research and was able to reset it. I thought that was odd, and very scary. It was the next day when I woke the iMac that I saw it had the black screen. This could be a coincidence.
Thanks,
Terri (noahsmom)